NORT 

RIMENT STATION 

UPPER DARBY PA R. W . MARQUIS DIRECTOR 

HEAVY SEED CROP FORECAST 

FOR VIRGINIA PINE IN 1953 

It is commonly believed that Virginia pine 

produces a good seed crop every year. However 

observation of seed fall at the Beltsville (~d. j 

Experimental Forest indicates a periodicity in - 

seed production by this species. Records from 

experimental plots during the past 3 years show 

these results : 

Cones matured Seed~~~~~cr

(year) 

Observation of cones on trees felled in the 

autumn of 1952 sabstantiates the existence of 

definite seed years. Figure 1 shows a defoliated Virginia pine branch that represents average cone production for the 1952 and 1953 seed 

crops. 

For one mature cone of the 1952 crop there 

are on this branch nine immature cones for the 

1953 crop. If all the immature cones ripen, the 
Cones of the 1952 and 1953 cone crops on a branch of 

a Virginia pine felled in autumn of 1952. In the 

large circle is a single cone of the 1952 crop. The 

small circles mark 9 cones of the 1953 crop. 

1953 seed crop should be nine times heavier than 

that produced in 1952. . 0 

Of course some cones will probably die before they mature. And the cones that mature 

(they usually mature early in ~ctober) may have 

fewer seeds than in former years. Nevertheless, 

an unusually good Virginia pine seed crop is 

forecast for 1953. 

--THOMAS Ws CHURCH, JRs 
I Caution must be used in planting tree seedlings in areas previously treated with herbicides to remove competition. In scrub oak lands 

in Pennsylvania nearly total failure resulted 

from planting 7 days or less after poisoning. 

r A small study was made at the DelawareLehigh Ekperimental Forest in the spring of 1952 

to test the efficacy of treating small planting 

spots just large enough for one tree seedling. 

Each spot was prepared by spraying a herbicide 

I on the brush and ground cover over an area about 

2 feet in diameter. 

I A 3-percent solution in oil of three parts 

2,4,5-T plus one part 2,4-D was used. The herbicide was sprayed on the brush and ground cover 

late in April and during the first week in May, 

while the brush was in dormant condition. 

Four to seven days after spraying, a seedling was planted in each spot. This short time 

lapse was scheduled with some misgiving, in fear 

that the herbicide might still be lethal at. the 

treated spot at planting time. No reliable information about this could be found, however; a 

few references merely said the herbicides "have 

little residual effect." 

Without a doubt the herbicide was lethal to 

most of the seedlings (table 1). None of the 

hardwood species survived. All the Japanese 

larch--not particularly robust stock--also died. 

Of the pines, only one block of red pine showed 

3 
Table 1.-Effaet of hqrMcide trontant on se- sunival 

a normal survival rate. We cannot explain this 

exception, for the original vegetation in the 

planting spots was thoroughly killed. 

How the herbicide kills the seedlings is 

not known. Since the herbicide was applied as a 

drenching spray, it is possible that the liquid 

entered the soil, killing the seedlings by residual toxicity. Another possibility is that 

the herbicide remained volatile for some time in 

the treated area. 

It has also been suggested that some of the 

poison may have come in contact with the seedlings during planting. But this possibility is 

somewhat remote. 

Species 

(md 8ga) 

The length of time the herbicide remains 

lethal is not known. Until more information is 

obtained, it is suggested that 6 months be allowed between herbicide treatment and planting. 

ESEL ~brcent zercmt Percent Percent 

' Red pins (3-0) 5 5 65 io 75 

Jack pine (2-0) 5 4 36* 18 45 

Pitch pine (2-0) 5 20 64 16 ' 72 

Japanese lareh (2-1) 4 0 92 0 24 

Black cherry (1-0) 3. 0 70 0 80 

~eIlc~-paphr (14) 7 0 86 0 74 . -. - 

*seed- nem difficult to M; actual sarvival nay be greater. 

Tiaa 

between 

treatdlent 

, and' 

planting 

Survival 

BlocK A Block 0 

d AGRICULTURE - FOREST SERV ICE - UPPER DARBY 

'Ireatsd lJntPted control mta ErK)';"